How does a control chart visually represent data?

A control chart visually represents data by plotting data points against control limits over time. This method allows for the monitoring of process behavior and performance, providing insights into the stability and variability of a process. Each data point on the control chart represents a measurement taken at a specific time, while the control limits help determine whether the process is in control or exhibiting signs of variation that may require investigation.

The use of control limits is essential because they define the expected range of variation in a process and help identify when a process is behaving outside these limits or when it is stable and predictable. If data points fall outside of these limits, it suggests that something might have changed in the process, prompting further analysis.

Other options, such as presenting average values only or summarizing key performance indicators, do not provide the visual tracking of process changes over time, which is a key feature of control charts. Displaying all data points in chronological order lacks the contextual comparison to control limits that makes control charts a powerful tool for process monitoring.